PROJECT SUMMARY/ ABSTRACT Heart replacement therapies (i.e., heart transplants and left ventricular assist devices) can improve advanced heart failure patients? morbidity, mortality, and quality of life. However, these therapies are associated with both high risks and potentially high rewards. An advanced heart failure patient?s path to receiving heart replacement therapies is dependent on 3 critical steps: (1) referral to an advanced heart failure center, (2) clinical evaluation at the center, and (3) case review by a multidisciplinary selection committee. This pathway is heterogeneous across the country leading to both underuse and overuse of therapies. There is an urgent need to study where and why these variations in use exist and to implement solutions that reduce unwarranted variations in care. The rationale that underlies the proposed research is that if we can understand the factors that lead to variations in heart replacement therapies at each of the three critical steps, we can develop standardized processes to ensure that heart failure patients who are most likely to benefit from these therapies have access to them, and those who are unlikely to qualify can move quickly to other treatment approaches most suited to their needs and preferences. This career development award includes three complementary aims. Aim 1 will quantitatively assess the degree of geographic variation at each of the three steps using Medicare claims and the Dartmouth Atlas hospital referral regions. Aim 2 will qualitatively assess reasons for variation by performing critical reviews of selection meetings and stakeholder interviews at advanced heart failure centers that are chosen based on findings from Aim 1. Aim 3 will use Delphi panels to rank factors contributing to unwarranted variation and propose potential solutions to reduce variation. A deeper understanding of variations in heart replacement therapy use coupled with expert-vetted proposed solutions for the leading problems will result in a R01 intervention trial that will address one or more of the modifiable factors and will help reduce unwarranted variations in use of heart replacement therapies. The applicant, an advanced heart failure cardiologist, proposes a five-year career development program to complement the research proposal. This incorporates close mentoring with Drs. Larry Allen (primary), Dan Matlock, and Fred Masoudi, nationally-renowned cardiovascular outcomes researchers with expertise in advanced heart failure, claims data, qualitative research, and shared decision-making. The candidate has built productive relationships with her mentors with four published manuscripts and two in progress and has a supportive institutional environment. To supplement her prior Masters in Public Health training, the candidate has developed a detailed didactic plan that includes training in Medicare claims data use, geographic analyses, qualitative methodology, and dissemination and implementation science. The candidate?s long-term goal is to improve equitable, judicious, patient-centered use of heart replacement therapies for patients with advanced heart failure. The proposed research, which serves as a key first step towards the applicant reaching her long-term goal, is significant because it will fill the existing gaps in knowledge to help reduce variations in use of heart replacement therapies.